CN110668474B - Method for preparing lithium chloride by using chlorine - Google Patents

Method for preparing lithium chloride by using chlorine Download PDF

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Publication number
CN110668474B
CN110668474B CN201910977486.7A CN201910977486A CN110668474B CN 110668474 B CN110668474 B CN 110668474B CN 201910977486 A CN201910977486 A CN 201910977486A CN 110668474 B CN110668474 B CN 110668474B
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lithium
chloride
chlorine
lithium chloride
solution
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CN110668474A (en
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洪侃
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Ganzhou Nonferrous Metallurgy Research Institute Co ltd
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01DCOMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00Lithium compounds
    • C01D15/04Halides
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00Physical properties of inorganic compounds
    • C01P2006/80Compositional purity

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
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  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

The invention discloses a method for preparing lithium chloride by using chlorine, which comprises the steps of reacting the chlorine with a lithium hydroxide solution to obtain a lithium hypochlorite solution, sequentially adding ammonium chloride and hydrogen peroxide, and evaporating and crystallizing to obtain the lithium chloride. The invention provides a step procedure for preparing lithium chloride by chlorine for the first time, and through theoretical calculation, ammonium chloride which has small Gibbs free energy and is easy to react is firstly added into a solution, and most of lithium hypochlorite in the solution is converted; and then hydrogen peroxide with high reaction limit is added for secondary chlorination, so that the defect of low purity of lithium chloride prepared by ammonium chloride is overcome, the problems of large using amount, high cost and the like of lithium chloride prepared by hydrogen peroxide are solved, and the method has the advantages of no introduction of new impurities, high purity of the obtained lithium chloride and the like.

Description

Method for preparing lithium chloride by using chlorine
Technical Field
The invention relates to a preparation method of lithium chloride, in particular to a method for preparing anhydrous lithium chloride by utilizing a large amount of pure chlorine generated by preparing metal by electrolyzing molten chloride, belonging to the field of chemical raw material preparation.
Background
Lithium chloride is increasingly demanded as a raw material for preparing metal lithium, a welding agent for metal alloy, a dehumidifying agent for air conditioner, a raw material for pharmaceutical industry and special cement, etc. The preparation method mainly comprises the following three methods: (1) the method adopts lithium hydroxide or lithium carbonate and hydrochloric acid to react to generate lithium chloride, and obtains anhydrous lithium chloride products after the procedures of separation, washing, concentration, crystallization, drying and the like; the method has the defects that the process needs to be subjected to the working procedures of washing, concentration and the like for many times, and the energy waste is large; (2) the direct conversion method of ore, said method regards spodumene concentrate as raw materials, convert spodumene concentrate into lithium sulfate at first, make lithium hydroxide or lithium carbonate from lithium sulfate, prepare anhydrous lithium chloride through the method (1) finally; the method has the disadvantages of long process flow, multiple operation procedures, large equipment investment and easy loss of lithium; (3) the method for extracting and producing lithium chloride from salt lake lithium ore comprises the process steps of acidification reaction, purification and impurity removal, chlorination reaction, freezing sodium precipitation, concentration lithium precipitation and the like.
At present, most of lithium metal production adopts an electrolytic melting lithium chloride electrolytic process, a large amount of pure chlorine gas can be generated, and in order to realize the problems of chlorine gas recycling, chlorine gas pollution and the like in industry, lithium hydroxide is generally used for absorbing chlorine gas to prepare lithium chloride, for example, as indicated in the text of research progress of application and production methods of lithium chloride published by Qinghai lake research institute of Chinese academy of sciences: lithium hydroxide and chlorine can be directly chloridized to prepare lithium chloride; the Ganxfeng lithium industry published 'technical method for producing lithium chloride by recycling electrolytic lithium metal chlorine', the text also indicates that: the preparation of lithium chloride from chlorine gas in the lithium hydroxide recovery and electrolysis process is feasible under the promotion of a catalyst. However, in the related reports published at present, lithium hypochlorite generated by absorbing chlorine gas by lithium hydroxide still belongs to the problem difficult to treat in the industry, although the problem of the lithium hypochlorite can be solved to a certain extent by adopting a catalyst, the added catalyst is usually ferric salt, nickel salt and the like, and excessive catalyst introduces impurities such as iron, nickel and the like, so that the impurities of the lithium chloride are easy to exceed the standard and the electrolysis cannot be carried out; the addition amount of the catalyst is small, hypochlorite cannot be fully treated, and further the production of lithium chloride by evaporation crystallization is a trough, so that certain potential safety hazard exists, and therefore, a safe and efficient process for preparing lithium chloride by chlorine is urgently needed to be developed.
Disclosure of Invention
In order to solve the defects of the existing chlorine recovery and lithium chloride preparation process, the invention aims to provide a method for preparing lithium chloride by using chlorine, firstly provides a step procedure for preparing lithium chloride by using chlorine, and firstly adds ammonium chloride which has small Gibbs reaction free energy and is easy to react into a solution by theoretical calculation to convert most of lithium hypochlorite in the solution; and then hydrogen peroxide with high reaction limit is added for secondary chlorination, so that the defect of low purity of lithium chloride prepared by ammonium chloride is overcome, the problems of large using amount, high cost and the like of lithium chloride prepared by hydrogen peroxide are solved, and the method has the advantages of no introduction of new impurities, high purity of the obtained lithium chloride and the like.
In order to achieve the technical purpose, the invention provides a method for preparing lithium chloride by using chlorine, which comprises the steps of reacting the chlorine with a lithium hydroxide solution to obtain a lithium hypochlorite solution, sequentially adding ammonium chloride and hydrogen peroxide, and evaporating and crystallizing to obtain the lithium chloride.
Preferably, the chlorine gas is high-temperature chlorine gas generated by electrolyzing and melting lithium chloride, and the chlorine gas is cooled to the temperature of less than or equal to 35 ℃.
Preferably, the molar ratio of the chlorine gas to the lithium hydroxide in the lithium hydroxide solution is 1: 2.0 to 2.4, and the concentration of the lithium hydroxide solution is 50 to 100 g/L.
When the invention uses the high-temperature chlorine generated by electrolyzing and melting the lithium chloride as the raw material, the chlorine is introduced into the excessive lithium hydroxide solution, thereby avoiding the generation of the excessive chlorine, realizing the zero emission of the chlorine and meeting the requirement of environmental-friendly production.
Preferably, the molar ratio of the added amount of the ammonium chloride to the lithium hypochlorite in the lithium hypochlorite solution is 0.01-0.04: 1, the reaction time is 10-30 min.
Preferably, the molar ratio of the added hydrogen peroxide to the lithium hypochlorite in the lithium hypochlorite solution is 0.008-0.016: 1, the reaction time is 10-30 min, and the mass fraction of the hydrogen peroxide is 30%.
The method utilizes chlorine generated by lithium chloride electrolysis to prepare lithium chloride, and introduces the chlorine into excessive lithium hydroxide solution, thereby avoiding the generation of excessive chlorine and realizing the recycling of the chlorine, thereby realizing zero emission of the chlorine and meeting the requirement of green production; in the process of preparing lithium chloride, the inventor researches and discovers that both ammonium chloride and hydrogen peroxide can effectively catalyze lithium hypochlorite to decompose into lithium chloride and oxygen, and simultaneously can react with the lithium hypochlorite to convert hypochlorite into chloride, and calculates the Gibbs free energy of the reaction of the ammonium chloride, the hydrogen peroxide and the lithium hypochlorite. This phenomenon is also confirmed in subsequent experiments, and in the experiments, the inventors found that, under the condition of coexistence of ammonium chloride and hydrogen peroxide, hydrogen peroxide can be decomposed into water and oxygen in a very short time because hydrogen peroxide does not participate in chlorination reaction of hypochlorous acid; the inventor also finds in experiments that the limit of conversion of hydrogen peroxide to lithium hypochlorite is higher than that of ammonium chloride, so in order to save reagent cost and improve conversion, the invention provides a process for chlorination treatment of lithium hypochlorite step by adding ammonium chloride first and then hydrogen peroxide. The invention converts lithium hypochlorite in lithium hydroxide absorption liquid into lithium chloride to the maximum extent, and the reaction equation is as follows:
Cl2+2LiOH=LiClO+LiCl+H2O
2LiClO=2LiCl+O2(g)
3LiClO+2NH4Cl=3LiCl+N2(g)+3H2O+3HCl
H2O2+LiClO=LiCl+H2O+O2(g)
compared with the existing lithium hypochlorite treatment process, the method has the advantages that new impurities cannot be introduced by using ammonium chloride and hydrogen peroxide to chlorinate lithium hypochlorite, the fractional catalytic treatment efficiency is high, and the purity of the obtained lithium chloride is high and can be not lower than 99.0%.
Compared with the prior art, the invention has the advantages that:
1. when high-temperature chlorine generated by electrolyzing and melting lithium chloride is used as a raw material, the chlorine is introduced into the excessive lithium hydroxide solution, so that the generation of the excessive chlorine is avoided, and the recycling of the chlorine is realized, so that the zero emission of the chlorine can be realized, and the requirement of green production is met;
2. according to the invention, the research on the chlorination efficiency in the preparation of lithium chloride is firstly carried out, the step procedure of preparing lithium chloride by chlorine is firstly provided, and by theoretical calculation, ammonium chloride which has small Gibbs free energy and is easy to react is firstly added into the solution, and most of lithium hypochlorite in the solution is converted; then adding hydrogen peroxide with high reaction limit for secondary chlorination. The invention not only solves the defect of low purity of the lithium chloride prepared by ammonium chloride, but also reduces the problems of large using amount, high cost and the like of the lithium chloride prepared by hydrogen peroxide by standardizing the adding sequence of the ammonium chloride and the hydrogen peroxide in the step-by-step process.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.
Example 1
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 20 ℃, and then, according to the mol ratio of the chlorine to LiOH of 1: 2.0 of the solution was absorbed by passing through 50g/L of LiOH solution to form a lithium hypochlorite solution, and then the molar ratio of lithium hypochlorite to ammonium chloride was 1: 0.01, adding ammonium chloride, reacting for 20min, and then mixing the lithium hypochlorite and hydrogen peroxide according to the molar ratio of 1: 0.008, adding 30 wt% of hydrogen peroxide, reacting for 10min, and evaporating and crystallizing to obtain anhydrous lithium chloride. The purity of the anhydrous lithium chloride was analyzed to be 99.10%.
Example 2
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 25 ℃, and then, according to the molar ratio of the chlorine to LiOH of 1: 2.2 absorption in 100g/L LiOH solution to form a lithium hypochlorite solution, then mixing the lithium hypochlorite solution with ammonium chloride according to the molar ratio of lithium hypochlorite to ammonium chloride of 1: 0.02, adding ammonium chloride, reacting for 10min, and then mixing the lithium hypochlorite and hydrogen peroxide according to the molar ratio of 1: 0.012 and 30 wt% of hydrogen peroxide is added, and after 30min of reaction, the anhydrous lithium chloride is obtained by evaporation and crystallization. The purity of the anhydrous lithium chloride was analyzed to be 99.25%.
Example 3
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to 35 ℃, and then, according to the mol ratio of the chlorine to LiOH of 1: 2.4 absorption in 75g/L LiOH solution to form a lithium hypochlorite solution, then mixing the lithium hypochlorite solution with ammonium chloride according to the molar ratio of lithium hypochlorite to ammonium chloride of 1: 0.04, adding ammonium chloride, reacting for 30min, and then mixing the lithium hypochlorite and hydrogen peroxide according to the molar ratio of 1: 0.016 is added with 30 wt% hydrogen peroxide, and after 20min of reaction, the anhydrous lithium chloride is obtained through evaporation crystallization and solid-liquid separation. The purity of the anhydrous lithium chloride was analyzed to be 99.09%.
Comparative example 1
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 25 ℃, and then, according to the molar ratio of the chlorine to LiOH of 1: 2.0 of the solution is added into 100g/L of LiOH solution for absorption to form a lithium hypochlorite solution, and then the molar ratio of lithium hypochlorite to ammonium chloride is 1: 0.02, adding ammonium chloride, reacting for 30min, and evaporating and crystallizing to obtain anhydrous lithium chloride. The purity of the anhydrous lithium chloride was analyzed to be 69.25%.
Comparative example 2
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 25 ℃, and then, according to the molar ratio of the chlorine to LiOH of 1: 2.4 introducing into 50g/L LiOH solution for absorption to form a lithium hypochlorite solution, and then, according to the molar ratio of lithium hypochlorite to hydrogen peroxide of 1: 0.01, adding 30 wt% of hydrogen peroxide, reacting for 30min, and evaporating and crystallizing to obtain anhydrous lithium chloride. The purity of the anhydrous lithium chloride was analyzed to be 79.25%.
Comparative example 3
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 25 ℃, and then, according to the molar ratio of the chlorine to LiOH of 1: 2.4 introducing the solution into 75g/L LiOH solution for absorption to form a lithium hypochlorite solution, and then mixing the lithium hypochlorite solution, ammonium chloride solution and hydrogen peroxide according to the molar ratio of 1: 0.04: 0.01, simultaneously adding 30 wt% of hydrogen peroxide, reacting for 30min, and evaporating and crystallizing to obtain anhydrous lithium chloride. The purity of the anhydrous lithium chloride was 89.09% by analysis.
Comparative example 4
Cooling high-temperature chlorine generated by electrolyzing and melting lithium chloride to the temperature of 25 ℃, and then, according to the molar ratio of the chlorine to LiOH of 1: 2.4 introducing the solution into LiOH solution of 100g/L for absorption to form lithium hypochlorite solution, and then, according to the molar ratio of lithium hypochlorite to hydrogen peroxide of 1: 0.016 is added with 30 wt% hydrogen peroxide to react for 10min, and the molar ratio of lithium hypochlorite to ammonium chloride is 1: 0.02, adding ammonium chloride, reacting for 30min, and evaporating and crystallizing to obtain anhydrous lithium chloride. The purity of the anhydrous lithium chloride was analyzed to be 90.09%.

Claims (6)

1. A method for preparing lithium chloride by using chlorine gas is characterized in that: reacting chlorine gas with a lithium hydroxide solution to obtain a lithium hypochlorite solution, firstly adding ammonium chloride, converting most of lithium hypochlorite in the solution into lithium chloride, then adding hydrogen peroxide, converting, and evaporating and crystallizing to obtain lithium chloride;
the molar ratio of the added amount of the ammonium chloride to the lithium hypochlorite in the lithium hypochlorite solution is 0.01-0.04: 1, the molar ratio of the added hydrogen peroxide to the lithium hypochlorite in the lithium hypochlorite solution is 0.008-0.016: 1.
2. the method for preparing lithium chloride by using chlorine gas as claimed in claim 1, wherein: the chlorine gas is high-temperature chlorine gas generated by electrolyzing and melting lithium chloride, and is cooled to the temperature of less than or equal to 35 ℃.
3. The method for preparing lithium chloride by using chlorine gas as claimed in claim 1, wherein: the mol ratio of the chlorine gas to the lithium hydroxide in the lithium hydroxide solution is 1: 2.0 to 2.4, and the concentration of the lithium hydroxide solution is 50 to 100 g/L.
4. The method for preparing lithium chloride by using chlorine gas as claimed in claim 1, wherein: the reaction time of the ammonium chloride and the lithium hypochlorite solution is 10-30 min.
5. The method for preparing lithium chloride by using chlorine gas as claimed in claim 1, wherein: the reaction time of the hydrogen peroxide and the lithium hypochlorite solution is 10-30 min, and the mass fraction of the hydrogen peroxide is 30%.
6. A process for preparing lithium chloride from chlorine as claimed in any of claims 1 to 5, wherein: the purity of the lithium chloride is not lower than 99.0%.
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Citations (8)

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Publication number Priority date Publication date Assignee Title
US3872220A (en) * 1974-01-24 1975-03-18 Foote Mineral Co Process for the production of lithium chloride
US6674781B1 (en) * 2002-08-19 2004-01-06 The Boeing Company Method and system for fueling a closed cycle chemical oxygen iodine laser
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CN1872688A (en) * 2006-06-12 2006-12-06 南通大学 Method for preparing lithium chloride free from water
CN101573296A (en) * 2006-11-02 2009-11-04 株式会社三德 Process for producing metallic lithium
CN108557768A (en) * 2018-02-27 2018-09-21 广东先导稀材股份有限公司 The preparation method of lithium hypochlorite
CN108584992A (en) * 2018-07-12 2018-09-28 赣州有色冶金研究所 A kind of method that vapor phase method prepares anhydrous lithium chloride
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Patent Citations (8)

* Cited by examiner, † Cited by third party
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US3872220A (en) * 1974-01-24 1975-03-18 Foote Mineral Co Process for the production of lithium chloride
US6674781B1 (en) * 2002-08-19 2004-01-06 The Boeing Company Method and system for fueling a closed cycle chemical oxygen iodine laser
RU2243158C2 (en) * 2003-01-22 2004-12-27 Открытое акционерное общество "Новосибирский завод химконцентратов" Lithium hydroxide chlorination method
CN1872688A (en) * 2006-06-12 2006-12-06 南通大学 Method for preparing lithium chloride free from water
CN101573296A (en) * 2006-11-02 2009-11-04 株式会社三德 Process for producing metallic lithium
CN108557768A (en) * 2018-02-27 2018-09-21 广东先导稀材股份有限公司 The preparation method of lithium hypochlorite
CN108584992A (en) * 2018-07-12 2018-09-28 赣州有色冶金研究所 A kind of method that vapor phase method prepares anhydrous lithium chloride
CN108793201A (en) * 2018-08-22 2018-11-13 上海氯德新材料科技有限公司 A kind of method of purification of lithium chloride conversion fluid

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